This invention relates to a fluid processing apparatus. More particularly, it relates to a fluid processing apparatus for processing blood, for example, to a heat exchanger for regulating the temperature of blood, an artificial lung for gas exchange in blood, a plasma separator or the like.
There is hither to known a heat exchanger in which is provided heat-exchange tubular means in the form of, for example, a plurality of heat-exchange fine tubes or a coiled tube. Also in an artificial organ such as an artificial lung, material-exchange fine tubes are provided. They are gas-exchange hollow fibers in an artificial lung or dialysis hollow fibers in an artificial kidney.
The above heat exchanger or artificial organ is used in the manner that blood is passed through the heat or material-exchange tubular means while a heat or material-exchange medium is passed between the tubular means and the housing.
In those apparatus, the heat or material-exchange tubular means is secured to the housing in a fluid tight seal by applying a potting composition, for example, a polyurethane base potting composition to form a partition.
However, there is the possibility that the potting composition forming the partition will shrink with time. The potting composition thus peels off the inner surface of the housing due to the shrinkage and thus does not maintain the fluid tight seal established during manufacturing.
Particularly, the shrinkage of the potting composition tends to occur at the periphery of the partition where the heat or material-exchange tubular means is not present. The reason is that the shrinkage of the potting composition is suppressed by the tubular means in the area where the heat or material-exchange tubular means is present while the suppression of the shrinkage is not effected in the area where the heat or material-exchange tubular means is not present. For this reason, for example, in the case of a heat exchanger in which the end of the housing is spread for connecting it to another fluid processing apparatus and which has a large annular area where the heat exchange tubular means is not present, there is the good possibility that the partition will peel off the inner surface of the housing due to shrinkage of the potting composition.
Although the potting composition may not be separated from the inner surface of the housing during a priming operation which is carried out prior to use of a fluid processing apparatus of this kind, there is the possibility that a weak bond portion is formed due to a shrinkage of the potting composition. If an impact is subsequently accidentally applied to such an apparatus when blood is passed therethrough for, for example, heat exchange, there is the risk that the partition well peel off the housing. Such a separation between the partition and the housing is very dangerous because heat-exchange fluid such as hot or cool water can mix with blood through the separated gap or crevice.